Evaluation of effective diffusion coefficient in various building materials and absorbents by mercury intrusion porosimetry

An effective diffusion coefficient plays an important role in the numerical analysis model to predict the emission rate of VOCs from building materials. This research evaluates the effective diffusion coefficient of VOCs (toluene, formaldehyde, etc.) in building materials (gypsum boards, medium density fiberboard, etc.) and adsorbents (activated carbon, charcoal, etc.) using the mercury intrusion porosimetry (MIP) test. The MIP test used in this study is convenient and useful, since it enables the effective diffusion coefficient to be obtained swiftly by producing the porosity and tortuosity factors in the test materials, and their molecular diffusion coefficient in air. In this paper, we measure the total porosities, pore size distributions, computed tortuosity factors and computed diffusion coefficients for various materials. Then, we demonstrate the relationship between their molecular weights and effective diffusion coefficients.